Image formation apparatus

ABSTRACT

An image formation apparatus according to one or more embodiments may include: an apparatus main body that includes an image formation section configured to form an image on a medium; a fixation device that includes a fixation member configured to heat the medium and is attachable to the apparatus main body in a first direction; and a temperature detector including a lens, provided in the apparatus main body, and configured to detect a temperature of the fixation member through the lens. An optical axis of the lens is inclined with respect to the first direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority based on 35 USC 119 from prior JapanesePatent Application No. 2021-46800 filed on Mar. 22, 2021, entitled“IMAGE FORMATION APPARATUS”, the entire contents of which areincorporated herein by reference.

BACKGROUND

The disclosure may relate to an image formation apparatus.

An image formation apparatus has been proposed in which an infraredtemperature sensor, which is a temperature detector that detects atemperature of a fixation member (e.g., a heating roller) of a fixationdevice that fixes a toner image on a medium, is provided outside thefixation device. See Patent Document 1: Japanese Patent ApplicationPublication No. 2008-225471

SUMMARY

In such an image formation apparatus, it may be preferable that thetemperature detector is not easily soiled.

An object of an embodiment of the disclosure may be to provide an imageformation apparatus capable of preventing a temperature detector, whichis provided in a main body of the image formation apparatus andconfigured to detect a temperature of a fixation member of a fixationdevice, from being easily soiled.

An aspect of the disclosure may be an image formation apparatus that mayinclude: an apparatus main body that includes an image formation sectionconfigured to form an image on a medium; a fixation device that includesa fixation member configured to heat the medium and is attachable to theapparatus main body in a first direction; and a temperature detectorincluding a lens, provided in the apparatus main body, and configured todetect a temperature of the fixation member through the lens. An opticalaxis of the lens is inclined with respect to the first direction.

According to the aspect described above, the image formation apparatuscan prevent the lens of the temperature detector from being easilysoiled.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an external perspective view of animage formation apparatus according to a first embodiment;

FIG. 2 is a diagram illustrating another external perspective view ofthe image formation apparatus illustrated in FIG. 1;

FIG. 3 is a diagram illustrating a schematic cross-sectional view of theimage formation apparatus of FIG. 1 or FIG. 2 taken along the lineIII-III;

FIG. 4 is a diagram illustrating a perspective view of a structureincluding a temperature detector and a partition member in the imageformation apparatus according to a first embodiment;

FIG. 5 is a diagram illustrating a perspective view of the structureillustrated in FIG. 4 with the partition member being omitted;

FIG. 6 is a diagram illustrating a perspective view of the partitionmember illustrated in FIG. 4;

FIG. 7A is a diagram illustrating a perspective view of the temperaturedetector and FIG. 7B is a diagram illustrating a perspective view of atemperature detection range by the temperature detector;

FIG. 8 is a diagram illustrating a perspective view of a side of thefixation device facing the temperature detector in the image formationapparatus according to a first embodiment;

FIG. 9 is a diagram illustrating a perspective view of a bottom portionof the fixation device illustrated in FIG. 8;

FIG. 10 is a diagram illustrating a perspective view of the structureillustrate in FIG. 8 with a cover member being omitted;

FIG. 11 is a diagram illustrating a schematic cross-sectional view forexplaining insertion and removal of the fixation device into and fromthe main body of the image formation apparatus according to a firstembodiment;

FIG. 12 is a diagram illustrating a schematic cross-sectional view of astate in which the fixation device is mounted to the main body of theimage formation apparatus according to a first embodiment;

FIG. 13 is a diagram illustrating an enlarged cross-sectional forexplaining an angle of an optical axis of a lens of the temperaturedetector with respect to a mounting direction of the fixation device inthe image formation apparatus according to a first embodiment;

FIG. 14 is a diagram illustrating a schematic cross-sectional view forexplaining insertion and removal of a fixation device into and from amain body of an image formation apparatus according to a secondembodiment;

FIG. 15 is a diagram illustrating an enlarged cross-sectional forexplaining an angle of an optical axis of a lens of a temperaturedetector with respect to a mounting direction of the fixation device inthe image formation apparatus according to a second embodiment;

FIG. 16 is a diagram illustrating a schematic cross-sectional view forexplaining insertion and removal of a fixation device into and from amain body of an image formation apparatus according to a thirdembodiment; and

FIG. 17 is a diagram illustrating an enlarged cross-sectional view forexplaining an angle of an optical axis of a lens of a temperaturedetector with respect to a mounting direction of the fixation device inthe image formation apparatus according to a third embodiment.

DETAILED DESCRIPTION

Descriptions are provided hereinbelow for one or more embodiments basedon the drawings. In the respective drawings referenced herein, the sameconstituents are designated by the same reference numerals and duplicateexplanation concerning the same constituents is omitted. All of thedrawings are provided to illustrate the respective examples only.

An image formation apparatus according to one or more embodiments isdescribed below with reference to the drawings.

The coordinate axes of the XYZ Cartesian coordinate system areillustrated in the figures to make it easier to understand therelationship between the figures. The X axis is a coordinate axisextending in a width direction of the image formation apparatus (i.e.,the width direction of the fixation device). The Y-axis is a coordinateaxis extending in a height direction of the image formation apparatusorthogonal to the X-axis. The Z-axis is a horizontal coordinate axisorthogonal to both the X-axis and the Y-axis. In the figures, the sameor similar configurations are designated by the same referencecharacters.

(1) First Embodiment

(1-1) Image Formation Apparatus

FIG. 1 is a diagram illustrating an external perspective view of animage formation apparatus 10 according to a first embodiment. FIG. 2 isa diagram illustrating another external perspective view of the imageformation apparatus 10. FIG. 3 is a diagram illustrating a schematiccross-sectional view of the image formation apparatus 10 of FIG. 1 orFIG. 2 taken along the line III-III.

The image formation apparatus 10 is, for example, an electrophotographicprinter. The image formation apparatus 10 is a monochrome printer. Theimage formation apparatus 10 may be a color printer. The image formationapparatus 10 includes an apparatus main body 100 including a housing ofthe image formation apparatus and a fixation device 200 (or a fixationunit) attachable and detachable to and from the apparatus main body 100.The apparatus main body 100 is provided with a media conveyance sectionthat conveys a medium 180 and an image formation section that forms animage on the medium 180. The image formation apparatus may be providedwith a reversing path (not illustrated) that reverses the front and backof the medium 180. The medium 180 is, for example, paper for printing.The medium 180 may be a printing medium such as an OHP sheet (overheadprojector sheet), an envelope, or the like.

The image formation section includes: a photosensitive drum 131 as animage carrier; a charging roller 132 as a charging device or a chargingmember configured to uniformly charge a surface of the photosensitivedrum 131; a development roller 133 as a developer carrier configured toattach a developer (toner) to an electrostatic latent image formed onthe surface of the photosensitive drum 131 so as to form a developerimage (toner image) on the surface of the photosensitive drum 31; and atoner supply roller 134 as a developer supply member disposed inpressure contact with the development roller 133. The toner supplyroller 134 supplies the toner supplied from a toner cartridge 135 to thedevelopment roller 133. A development blade is pressed against thedevelopment roller 133. The development blade makes a thin layer of thetoner supplied from the toner supply roller 134 on the developmentroller 133.

Above the photosensitive drum 131 (in the +Y direction), a print head141, serving as an exposure device, that includes a plurality ofsemiconductor light emitting elements arranged in a line(s) in the Xdirection and is arranged so as to be opposed to the photosensitive drum131. The print head is also referred to as a light emitting element(LED) head or a light emitting element (LED) array head. The print head141 exposes the uniformly charged photosensitive drum 131 with lightaccording to image data so as to form an electrostatic latent imagebased on the image data on the surface of the photosensitive drum 131.The semiconductor light emitting elements in the print head 141 are, forexample, light emitting diodes (LED) or light emitting thyristors.

A transfer unit is provided below the photosensitive drum 131 (in the −Ydirection). The transfer unit is provided with a transfer roller 151 asa transfer member. The transfer roller 151 is disposed so as to beopposed to the photosensitive drum 131. The transfer roller 151 chargesthe medium 180 passing through a transfer position with a polarityopposite to that of the toner, and thus transfers the toner image fromthe photosensitive drum 131 to the medium 180.

A paper feed mechanism configured to supply the medium 180 is providedin a lower part of the apparatus main body 100. The paper feed mechanismincludes a media storage cassette 110, a hopping roller 111, a resistroller 112, and a roller pair 113 and a roller pair 114 configured toconvey the medium 180 along guides 121 and 122.

A fixation device 200 is mounted (attached) in an accommodation section190 (an accommodation recess) for accommodating therein the fixationdevice 200 in the apparatus main body 100. The fixation device 200includes a fixation roller (i.e., a heating roller) serving as afixation member and a backup roller (i.e., a pressure roller) serving asa pressure member. The fixation device 200 pressurizes and heats thetoner image transferred on the medium 180 so as to fix the toner imageto the medium 180. On a media discharge side of the fixation device 200,a roller 115, a guide 123, a roller 116, a roller 117, and a mediastacker (media loading section) are provided.

Next, an operation of the image formation apparatus 1 is described.First, the media 180 loaded in the media storage cassette 110 are takenout one by one by the hopping roller 111 and sent to the resist roller112. The medium 180 that is taken out is fed along the guides 121 and122 from the resist roller 112 and is conveyed to the image formationsection. In the image formation section, the surface of thephotosensitive drum 131 is uniformly charged by the charging roller 132and exposed by the print head 141, so that the electrostatic latentimage is formed on the surface of the photosensitive drum 131. Thethin-layered toner on the development roller 133 is electrostaticallyadhered to the electrostatic latent image, so as to form a toner imageon the surface of the photosensitive drum 131. The toner image on thephotosensitive drum 131 is transferred to the medium 180 by the transferroller 151, so as to form a toner image on the medium 180. Aftertransferring of the toner image to the medium 180, the toner remainingon the photosensitive drum 131 is removed by a cleaning device (notillustrated). The medium 180 on which the toner image has been formed isconveyed to the fixation device 200. In the fixation device 200, thetoner image on the medium 180 is fixed to the medium 180, so that animage corresponding to the toner image is formed (printed) on the medium180. The medium 180 on which the image has been formed (printed) isdischarged to the media stacker, by the rollers 115, 116, and 117.Through this process, the image is formed (printed) on the medium 180.

(1-2) Fixation Device and Temperature Detector

FIG. 4 is a diagram of a perspective view illustrating a structureincluding a temperature detector 160 and a partition member 170 of theimage formation apparatus 10. FIG. 5 is a diagram illustrating aperspective view of the structure illustrated in FIG. 4 with thepartition member 170 being omitted. FIG. 6 is a diagram illustrating aperspective view of the partition member 170 illustrated in FIG. 4. FIG.7A is a diagram illustrating a perspective view of the temperaturedetector 160 illustrated in FIG. 3, and FIG. 7B is a diagramillustrating a perspective view of a temperature detection range A2which is an area where the temperature detector 160 detects thetemperature. The temperature detector 160 is, for example, a thermopile.The thermopile is a detection device including a lens 161, which is anoptical system including a light incident surface (i.e., a window), anda sensor (not illustrated) that detects a temperature based on light(infrared light) passing through the lens 161. The light incidentsurface is the surface of the lens 161.

FIG. 8 is a diagram illustrating a perspective view of the fixationdevice 200 of the image formation apparatus 10. FIG. 9 is a diagram of aperspective view illustrating a bottom portion of the fixation device200 illustrated in FIG. 8. FIG. 10 is a diagram illustrating aperspective view of the structure illustrated in FIG. 8 with the covermember 210 being omitted. FIG. 11 is a diagram of a schematiccross-sectional view for explaining the process of inserting andwithdrawing the fixation device 200 in insertion and withdraw directionsD (i.e., an insertion direction and a withdrawal direction) into andfrom the accommodation section 190 of the apparatus main body 100. FIG.12 is a diagram of a schematic cross-sectional view illustrating a statein which the fixation device 200 is mounted to the apparatus main body100 of the image formation apparatus 10. FIG. 13 is a diagramillustrating an enlarged cross-sectional for explaining an angle θ of anoptical axis A1 of the lens 161 of the temperature detector 160 withrespect to a mounting direction D1 (an attaching direction D1) of thefixation device 200 to the image formation apparatus 10. The mountingdirection D1 is also referred to as the insertion direction.

The detection range A2 of the temperature detector 16 is illustrated inFIGS. 4, 5, and 7B. As illustrated in FIGS. 11 to 13, the apparatus mainbody 100 includes a mounting portion in which the temperature detector160 is to be mounted.

A blower fan 174 (an air blowing fan) is provided above (on the +Y sideof) the temperature detector 160. The partition member 170 is providedbetween the temperature detector 160 and the fixation deviceaccommodation section 190 to partition between the temperature detector160 and the fixation device 200. The partition member 170 is providedwith airflow holes 173 through which air blown from the blower fan 174passes. The air that has been passed through the airflow holes 173passes through the accommodation section 190 that accommodates thereinthe fixation device 200, so as to cool the surroundings of the fixationdevice 200.

As illustrated in FIGS. 4, 6, and 11 to 13, a first through hole 171,which is like a peephole for the temperature detector 160, is formed inthe partition member 170. In other words, the partition member 170includes the first through hole 171 facing the lens 161 of thetemperature detector 160. The partition member 170 is provided withconvex portions 172 formed by processing a sheet metal for the partitionmember 170 and protruding toward the fixation device 200 at upper,right, and left sides of first through hole 171 (i.e., an upper portionof a periphery (an outer circumference) of the first through hole 171).The shape of the convex portion 172 is not limited to the oneillustrated in the figures. Although it is possible not to include theconvex portion 172, it may be preferable to include the convex portion172 in light of preventing the lens 161 from being easily soiled.

As illustrated in FIGS. 8, 9, and 11 to 13, a second through hole 211,which is like a peep hole, is formed in the cover member 210 thatsurrounds the fixation roller 230. The cover member 210 includes thesecond through hole 211 facing and being aligned with the first throughhole 171. The cover member 210 of the fixation device 200 is providedwith a concave portion 212 (a recessed portion 212) around the secondthrough hole 211. The second through hole 211 is formed in the concaveportion 212 of the cover member 210 of the fixation device 200, that is,the second through hole 211 is formed at the bottom of the concaveportion 212 of the cover member 210 of the fixation device 200. Thetemperature detector 160 detects the temperature of the fixation roller230 through the first through hole 171 of the partition member 170 andthe second through hole 211 of the cover member 210 of the fixationdevice 200. The shape of the concave portion 212 is not limited to theone illustrated in the figures.

The temperature detector 160 is provided on the upstream side (i.e.,approximately in the −Z direction) in a medium conveyance direction(approximately in the Z direction in the fixation device 200) of thefixation device accommodation section 190. The fixation device 200 isdetachably mounted in the accommodation section 190 of the apparatusmain body 100.

The air blown from the blower fan 174 through the airflow holes 173 isdirected to a downstream side in the medium conveyance direction(approximately in the +Z direction). A gap 175 (or a clearance 175) isprovided between the fixation device 200 and the partition member 170.The fixation device 200 and the partition member 170, which form the gap175 therebetween, include the concave portion 212 and a convex portion172, respectively. The concave portion 212 and the convex portion 172form a detour structure, a maze structure, or the like between thefixation device 200 and the partition member 170 and thus make itdifficult for the air blown by the blower fan 174 to reach the lens 161of the temperature detector 160, so as to prevent the lens 161 frombeing soiled

An upper edge (an edge in the +Z direction) of the first through hole171 is located on a downstream side in the mounting direction D1 than anupper end (an end in the +Z direction) of the surface of the lens 161 ofthe temperature detector 160. A bottom wall 170 b of the partitionmember 170 is provided between the temperature detector 160 and themedium conveyance path along which the medium 180 is conveyed and thusseparates the temperature detector 160 from the medium conveyance path.The bottom wall 170 b of the partition member 170 is arranged in amanner that the bottom wall 170 b of the partition member 170 approachesthe optical axis A1 of the temperature detector 160 as it goes thedownstream side (the +Z direction in FIG. 13) in the medium conveyancedirection.

The fixation device 200 includes a fixation roller 230, which is afixation member (heating member) configured to heat the medium 180, anda pressure roller 240 configured to be pressed against the fixationroller 230. The fixation roller 230 may be replaced with a rotatingfixation belt. In the state where the fixation device 200 is mounted inthe accommodation section 190 of the apparatus main body 100, theoptical axis A1 of the lens 161 is inclined at a predetermined angle θrelative to the mounting direction D1. It is preferable that thetemperature detector 160 be provided in the apparatus main body 100 withthe optical axis A1 intersecting the fixation roller 230 in terms ofimproving the sensitivity of detection of the temperature. It is evenmore preferable that the optical axis A1 intersects a rotation axis C0(a center axis C0) of the fixation roller 230, in terms of improving thesensitivity of detection of the temperature.

It is also preferable, in order to detect the temperature of thefixation roller 230 at a position close to the nip position 250, thatthe optical axis A1 intersects the surface of the fixation roller 230 atan upstream side, in the rotation direction of the fixation roller 230,from a nip position 250, which is a contact position between thefixation roller 230 and the medium 180.

The temperature detector 160 is provided in the apparatus main body 100in a manner that the optical axis A1 points diagonally downward withrespect to the horizontal direction (Z direction). With thisconfiguration, dust, toner, or the like floating around the fixationdevice 200 is less likely to be adhered to the surface of the lens 161.

However, in a modification, the temperature detector 160 may be providedin the apparatus main body 100 in a manner that the optical axis A1extends diagonally upward with respect to the horizontal direction (Zdirection). In such a case, the dust, toner, or the like tends to beadhered to the surface of the lens 161 to some extent, but thetemperature at a position close to the nip position 250 of the fixationroller 230 can be detected.

In the state where the fixation device 200 is mounted to the apparatusmain body 100, the optical axis A1 of the lens 161 is inclined at apredetermined angle θ relative to the mounting direction D1, wherein theangle θ is, for example, within a range of 1° or more and 179° or less(i.e., 1°≤θ≤179°).

If the angle θ is out of the range of 1° or more and 179° or less, thesurface of the optical lens substantially orthogonal to the optical axisA1 is located directly in front of the fixation device 200 in themounting direction D1 upon mounting (inserting) the fixation device 200to the apparatus main body 100. Therefore, the air flowing in themounting direction D1, which is generated when the fixation device 200is pushed in the mounting direction D1, hits the surface of the lens 161more, to increase the amount of the dust, the toner, or the like adheredto the surface of the lens 161.

To the contrary, in the image formation apparatus 10 according to afirst embodiment, the optical axis A1 of the lens 161 is inclined at theangle θ with respect to the mounting direction D1. Accordingly, the airflowing in the mounting direction D1, which is expected to occur mostwhen the fixation device 200 is pushed in the mounting direction D1, isless likely to hit the surface of the lens 161, so as to reduce theamount of the air that hits the surface of the lens 161 when the airflows in the mounting direction D1. With this configuration, the amountof the dust, the toner, or the like adhered to the surface of the lens161 is reduced.

In the image formation apparatus 10 according to a first embodiment, itmay be preferable that the angle θ is within a range of 30° or more and150° or less (i.e., 30°≤θ≤150°). In this case, since the optical axis A1of the lens 161 is inclined at the angle of 30° or more with respect tothe mounting direction D1, the amount of the air that hits the surfaceof the lens 161 is reduced, when the air flows in the mounting directionD1, which is generated by the wind pressure upon inserting the fixationdevice 200 in the mounting direction D1. Therefore, the amount of thedust, toner, or the like adhered to the surface of the lens 161 isreduced.

In the image formation apparatus 10 according to a first embodiment, itmay be more preferable that the angle θ is within a range of 90° or moreand 150° or less (i.e., 90°≤θ≤150°). In this case, since the opticalaxis A1 of the lens 161 is inclined at the angle of 90° or more withrespect to the mounting direction D1, the amount of the air that hitsthe surface of the lens 161 is further reduced, when the air flows inthe mounting direction D1, which is generated by the wind pressure uponinserting the fixation device 200 in the mounting direction D1.Therefore, the amount of the dust, the toner, or the like adhered to thesurface of the lens 161 is further reduced.

The partition member 170 is formed with the plurality of airflow holes173 through which the air sent from the blower fan 174 passes, and theconvex portion 172 provided at the periphery of the first through hole171 and thus provided between the first through hole 171 and theplurality of airflow holes 173. The cover member 210 includes theconcave portion 212 opposed to the convex portion 172 and formed withthe second through hole 211.

When the fixation device 200 is mounted in the fixation deviceaccommodation section 190 of the apparatus main body 100, the dust,toner or the like inside or outside the accommodation section 190 isflown up. Although the dust, toner, or the like falls down in thedirection of gravity after being flown up, the dust, toner, or the likeis less likely to be adhered to the surface of the lens 161 because thesurface of the lens 161 of the temperature detector 160 faces thedownstream side of the mounting direction D1 of the fixation device 200.

When the blower fan 174 is activated to start blowing the air during theprinting operation of the image formation apparatus 10, the dust, toner,or the like inside or outside the apparatus main body 100 is blown upand is blown into the fixation device accommodation section 190 togetherwith the blown air. Because of the gap 175 between the fixation device200 and the partition member 170, the air sent by the blower fan 174flows through the gap 175 toward the inside of the accommodation section190 of the fixation device 200. However, since the convex portion 172 isprovided around the first through hole 171 of the partition member 170,and the concave portion 212 of the cover member 210 overlaps the convexportion 172 of the partition member 170 with the gap therebetween, it isdifficult for the dust, the toner, or the like raised by the wind fromthe blower fan 174 to pass the first through hole 171 via the gap 175.Therefore, it is less likely for the dust, the toner, or the like blownwith the air to be adhered to the surface of the lens 161.

The toner image formed in the image formation section is transferred tothe medium 180, is conveyed to the fixation device 200 in the Edirection, and fixed to the medium 180 in the fixation device 200. Sincethe toner on the medium 180 being conveyed under the temperaturedetector 160 is unfixed before the toner is fixed to the medium 180 bythe fixation device 200, the unfixed toner may soar up from the medium180 to a certain height and fall down. In a first embodiment, the bottomwall 170 b of the partition member 170, which is provided below thetemperature detector 160, is inclined with respect to the mediumconveyance path (see FIG. 12) in such a manner that a downstream endportion, in the medium conveyance direction, of the bottom wall 170 b isprovided farther from the media conveyance path, than an upstream endportion, in the medium conveyance direction, of the bottom wall 170 b.That is, as illustrated in FIG. 12, a distance L1 from the downstreamend portion of the bottom wall 170 b to the medium conveyance path inthe vertical direction is greater than a distance L2 from the upstreamend portion of the bottom wall 170 b to the medium conveyance path inthe vertical direction. Accordingly, the unfixed toner on the mediumbeing conveyed in the medium conveyance path is less likely to beattached to the downstream side of the bottom wall 170 b (which isprovided on a side closer to the through hole 171) than the upstreamside of the bottom wall 170 b (which is provided on a side farther fromthe through hole 171). Therefore, this configuration suppresses theunfixed toner on the medium being conveyed along the medium conveyancepath from being adhered to the temperature detector 160, which isprovided above the bottom wall 170 b of the partition member 170.

(1-3) Effects

As described above, in a first embodiment, although the dust, the toner,or the like is scattered when the fixation device 200 is inserted orremoved, the dust, toner, or the like is less likely to be adhered tothe lens 161 of the temperature detector 160. Therefore, temperaturedetection failure and printing failure are less likely to occur.

The concave portion 212 of the cover member 210 of the fixation device200 and the convex portion 172 of the partition member 170 overlap eachother with the gap therebetween. This configuration suppresses the dust,the toner, or the like that is blown by the blower fan 174 during theoperation of the image formation apparatus from being adhered to thesurface of the lens 161 of the temperature detector 160. Therefore, thetemperature detection failure is less likely to occur even during theoperation of the image formation apparatus. Further, even when theunfixed toner flies from the medium, this configuration suppresses theunfixed toner from being adhered to the detection part of thetemperature detector 160, so as to suppress the temperature detectionfailure.

(2) Second Embodiment

In a first embodiment, the case has been described in which the fixationdevice 200 is inserted in the mounting direction D1 from the upperopening of the accommodation section 190 of the apparatus main body 100.In a second embodiment, an example is described in a fixation device 200a is inserted in a mounting direction D1 from a side opening of anaccommodating portion 190 a of an apparatus main body 100 a.

FIG. 14 is a diagram of a schematic cross-sectional view for explainingthe process of inserting and removing the fixation device 200 a into andfrom the accommodation section 190 a of the apparatus main body 100 a ofthe image formation apparatus 10 a according to a second embodiment.FIG. 15 is a diagram of a schematic cross-sectional view for explainingan angle θ of the optical axis A1 of the lens 161 of the temperaturedetector 160 with respect to the mounting direction D1 of the fixationdevice 200 a to be mounted in the accommodation section 190 a of theapparatus main body 100 a of the image formation apparatus 10 a.

As illustrated in FIGS. 14 and 15, in a second embodiment, the opticalaxis A1 of the lens 161 is also inclined at the angle θ, relative to themounting direction D1, which is the first direction. In the state wherethe fixation device 200 a is mounted in the accommodation section 190 aof the apparatus main body 100 a, the optical axis A1 of the lens 161 isinclined at the predetermined angle θ relative to the mounting directionD1, wherein the angle θ is, for example, within a range of 1° or moreand 179° or less (i.e., 1°≤θ≤179°).

In the image formation apparatus 10 a according to a second embodiment,since the optical axis A1 of the lens 161 is inclined at the angle θwith respect to the mounting direction D1, the amount of the air thathits the surface of the lens 161 becomes small, when the air flows inthe mounting direction D1, which is considered to be generated most bythe wind pressure upon pushing the fixation device 200 s in the mountingdirection D1. As a result, this configuration suppresses the dust, thetoner, or the like floating in the air from being adhered to the surfaceof the lens 161.

In the image formation apparatus 10 a according to a second embodiment,it may be preferable that the angle θ is within a range of 30° or moreand 150° or less (i.e., 30°≤θ≤150°). In this case, since the opticalaxis A1 of the lens 161 is inclined at the angle of 30° or more withrespect to the mounting direction D1, the amount of the air that hitsthe surface of the lens 161 is reduced, when the air flows in themounting direction D1, which is generated upon pushing the fixationdevice 200 a in the mounting direction D1. As a result, thisconfiguration further suppresses the dust, the toner, or the likefloating in the air from being adhered to the surface of the lens 161.

In the image formation apparatus 10 a according to a second embodiment,it may be further preferable that the angle θ is within a range of 30°or more and 90° or less (i.e., 30°≤θ≤90°). In this case, since theoptical axis A1 of the lens 161 is inclined at the angle of 30° or morewith respect to the mounting direction D1, the amount of the air thathits the surface of the lens 161 is further reduced, when the air flowsin the mounting direction D1, which is generated upon pushing thefixation device 200 a in the mounting direction D1. As a result, theconfiguration further suppresses the dirt such as the dust, the toner,or the like from being adhered to the surface of the lens 161.

Except for the configurations described above, a second embodiment isthe same as a first embodiment.

(3) Third Embodiment

In a first embodiment, the case has been described in which the fixationdevice 200 is inserted in the mounting direction D1 from the upperopening of the accommodation section 190 of the apparatus main body 100.In a third embodiment, an example is described in which a fixationdevice 200 b is inserted in the mounting direction D1 from a sideopening of an accommodation section 190 b of an apparatus main body 100b, and the temperature detector 160 detects the temperature of thefixation roller 230 through a first through hole 171 b and a secondthrough hole 211 b from above the fixation device 200 b.

FIG. 16 is a diagram of a schematic cross-sectional view illustratingthe process of inserting and removing the fixation device 200 b to andfrom the accommodation section 190 b of the apparatus main body 100 b ofan image formation apparatus 10 b according to a third embodiment. FIG.17 is a diagram of a schematic cross-sectional view for explaining anangle θ of the optical axis A1 of the lens 161 of the temperaturedetector 160 with respect to the mounting direction D1 of the fixationdevice 200 b to be mounted in the accommodation section 190 b of themain body 100 b of the image formation apparatus 10 b.

As illustrated in FIGS. 16 and 17, in a third embodiment, the opticalaxis A1 of the lens 161 is also inclined at the angle θ relative to themounting direction D1 serving as the first direction. In the state wherethe fixation device 200 b is mounted in the accommodation section 190 bof the main body 100 b, the optical axis A1 of the lens 161 is inclinedat the predetermined angle θ relative to the mounting direction D1,wherein the angle θ is, for example, within a range of 1° or more and179° or less (i.e., 1°≤θ≤179°).

In the image formation apparatus 10 b according to a third embodiment,since the optical axis A1 of the lens 161 is inclined at the angle θwith respect to the mounting direction D1, the amount of the air thathits the surface of the lens 161 becomes small, when the air flows inthe mounting direction D1, which is considered to be generated most bythe wind pressure upon pushing the fixation device 200 b in the mountingdirection D1. As a result, this configuration suppresses the dust, thetoner, or the like floating in the air from being adhered to the surfaceof the lens 161.

In the image formation apparatus 10 b according to a third embodiment,it may be preferable that the angle θ is within a range of 30° or moreand 150° or less (i.e., 30°≤θ≤150°). In this case, since the opticalaxis A1 of the lens 161 is inclined at the angle of 30° or more withrespect to the mounting direction D1, the amount of the air that hitsthe surface of the lens 161 is reduced, when the air flows in themounting direction D1, which is generated upon pushing the fixationdevice 200 b in the mounting direction D1. As a result, thisconfiguration suppresses the dust, the toner, or the like floating inthe air from being adhered to the surface of the lens 161.

In the image formation apparatus 10 b according to a third embodiment,it may be more preferable that the angle θ is within a range of 90° ormore and 150° or less (i.e., 90°≤θ≤150°). In this case, since theoptical axis A1 of the lens 161 is inclined at the angle of 90° or morewith respect to the mounting direction D1, the amount of the air thathits the surface of the lens 161 is further reduced, when the air flowsin the mounting direction D1, which is generated upon pushing thefixation device 200 b in the mounting direction D1. As a result, theconfiguration further suppresses the dirt such as the dust, toner, orthe like from being adhered to the surface of the lens 161.

Except for the configurations described above, a third embodiment is thesame as a first embodiment.

(4) Modification

In one or more embodiments described above, the case has been describedin which the image formation apparatus includes only one process unitwhich configured to form a toner image and transfer the toner image tothe medium 180 being conveyed. However, the disclosure is not limitedthereto. The disclosure is applicable to an image formation apparatusthat transfers a toner image to a medium 180 via an intermediatetransfer belt, and an image formation apparatus that forms a color imageusing a plurality of process units.

Further, in one or more embodiments described above, the case has beendescribed in which the image formation apparatus is a printer. However,the disclosure is applicable to an image formation apparatus which is acopier, a facsimile machine, a multifunction machine, or the like.Further, the disclosure is also applicable to other devices, wherein adevice main body is equipped with a temperature detector and a unit isinserted into an accommodation section in the device main body.

The invention includes other embodiments or modifications in addition toone or more embodiments and modifications described above withoutdeparting from the spirit of the invention. The one or more embodimentsand modifications described above are to be considered in all respectsas illustrative, and not restrictive. The scope of the invention isindicated by the appended claims rather than by the foregoingdescription. Hence, all configurations including the meaning and rangewithin equivalent arrangements of the claims are intended to be embracedin the invention.

1. An image formation apparatus comprising: an apparatus main body that includes an image formation section configured to form an image on a medium; and a fixation device that includes a fixation member configured to heat the medium and is attachable to the apparatus main body in a first direction; and a temperature detector including a lens, provided in the apparatus main body, and configured to detect a temperature of the fixation member through the lens, wherein an optical axis of the lens is inclined with respect to the first direction.
 2. The image formation apparatus according to claim 1, wherein the temperature detector is provided in the apparatus main body in a manner that the optical axis intersects the fixation member.
 3. The image formation apparatus according to claim 2, wherein the fixation member is a rotating roller or a rotating belt, and the optical axis intersects the fixation member at a position upstream, in the rotation direction of the fixation member, from a contact position between the fixation member and the medium.
 4. The image formation apparatus according to claim 2, wherein the optical axis intersects a rotation axis of the fixation member.
 5. The image formation apparatus according to claim 1, wherein the temperature detector is provided in the apparatus main body in a manner that the optical axis is oriented diagonally downward with respect to a horizontal direction.
 6. The image formation apparatus according to claim 1, wherein the temperature detector is provided in the apparatus main body in a manner that the optical axis is oriented diagonally upward with respect to a horizontal direction.
 7. The image formation apparatus according to claim 1, wherein an angle of the optical axis with respect to the first direction is within a range of 1 degree or more and 179 degrees or less.
 8. The image formation apparatus according to claim 1, wherein an angle of the optical axis with respect to the first direction is within a range of 30 degrees or more and 150 degrees or less.
 9. The image formation apparatus according to claim 1, wherein an angle of the optical axis with respect to the first direction is within a range of 90 degrees or more and 150 degrees or less.
 10. The image formation apparatus according to claim 1, further comprising a partition member provided in the apparatus main body and dividing a space between the temperature detector and the fixation device, wherein the fixation device further includes a cover member covering the fixation member, the partition member includes a first through hole facing the lens, and the cover member includes a second through hole facing the first through hole in a manner that the temperature detector is provided to detect the temperature of the fixation member through the first through hole and the second through hole.
 11. The image formation apparatus according to claim 10, wherein the partition member further includes an airflow hole through which air sent from the apparatus main body passes and a convex portion formed around the first through hole and provided at a position between the airflow hole and the first through hole, and the cover member further includes a concave portion in which the second through hole is provided and that faces the convex portion.
 12. The image formation apparatus according to claim 1, wherein the apparatus main body includes an accommodation section including an upper opening, and the fixation device is inserted from the upper opening into the accommodation section in the first direction.
 13. The image formation apparatus according to claim 1, wherein the apparatus main body has an accommodation section including an opening on a side of the accommodation section, and the fixation device is inserted from the opening into the accommodation section in the first direction. 